Field of the Invention
The present invention relates to methods of assigning workload instances among a plurality of servers.
Background of the Related Art
The power and cooling demands of large computing systems continue to increase. Data centers are currently being challenged to both sustain the increasing information technology (IT) demand, as well as to reduce energy spending and carbon footprint. Today, data centers consume 3-5% of the total world energy consumption. Of this amount, at least 35% is associated with data center cooling management, 10% is consumed by power distribution units, 5% is the overhead and the remaining 50% is the compute power. Furthermore, rack level power demand is expected to increase by 10-20% between 2015 and 2020. In some implementations, racks are already being partially populated for this very reason.
Given these power trends, there has been tremendous focus in trying to optimize data center designs to recover rack space for IT and save energy. In order to achieve this, much attention has been given to the design of the mechanical systems such as chillers, free air economizers, high efficiency power distribution, and premium power supplies units. Further reductions in energy consumption and efficiency may be achieved by improving the individual components of the servers and other IT equipment.
Inside a typical air-cooled server, heat is generated mainly by the CPU, but also by the power supplies, memory, data storage device, networking controller, core chipset, and so on. As the amount of heat goes up, the fans have to run faster to remove that heat, but the relationship is not linear between power input to the fans and how effectively heat is removed. In fact, where the amount of heat energy removed increases linearly, the power to remove it increases by the cube.
Since an idle server still consumes power, some methods of power conservation will consolidate workload from several lightly-loaded servers to one heavily loaded server, and then suspend or shut-down the idled servers. However, this method requires suspend/resume capability be enabled, which is rarely something datacenter operators are willing to do. Furthermore, this method is also based on the mistaken assumption that the few heavily loaded servers are operating efficiently.